IFN-g is a dimerized soluble cytokine that is the only member of the type II class of interferons. The importance of IFNg in the immune system stems in part from its ability to inhibit viral replication directly and most importantly from its immunostimulatory and immunomodulatory effects. Studies show that IFN-gamma can rapidly regulate STAT activation by IL-10 and alters macrophage responses to IL-10. Thus a functional binding ELISA assay was conducted to detect the interaction of recombinant pig IFN-g and recombinant pig IL-10. Briefly, IFN-g was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to IL-10-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-IFN-g pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 µL stop solution to the wells and read at 450/630 nm immediately. The binding activity of recombinant pig IFN-g and recombinant pig IL-10 was shown in Figure 1, the EC50 for this effect is 3.1 ug/mL.